Field of the Invention
The present invention relates to an acellular dermal graft, and a method of preparing the same.
Discussion of Related Art
Skin tissues of a human body are mainly divided into three parts: epidermis composed of the outermost layers of cells in the skin; dermis lined under the epidermis; and subcutaneous tissue. Among these, the epidermis is composed of epithelial cells in which a basement membrane capable of strongly binding the dermis to the epidermis is differentiated into various layers, and the other components such as melanocytes, and immune cells, and the dermis lined under the epidermis is composed mainly of fibroblasts and various extracellular matrixes secreted from the fibroblasts.
Some skin tissues or internal organ tissues may be injured by burns, external wounds, sores, etc. Here, a method of transplanting the patient's own skin tissue or internal organ tissue is used to heal the injured tissue or to carry out reconstructive plastic surgery. In this case, since skin tissue or organ tissue should be extracted from the patient who is to receive the transplant, the patient must undergo a substantial amount of surgery. It may be dangerous to carry out transplantation when the patient is not healthy. In addition, there is a method of performing transplantation using a xenograft or synthetic biomaterial. In this case, the patent may receive additional surgery due to an inflammatory response caused by an immune rejection response when the patient carries the transplant for a long period of time. To solve the problem, a method of preparing an acellular dermis for transplantation from a skin tissue extracted from a donor (Korean Patent Publication No. 2001-0092985, and Korean Patent No. 791502) and performing an operation is used as a method used to solve the difficulties.
Basically, when a graft is inserted in a host tissue of a human body, the graft causes various problems such as blockage of blood flow and bodily fluid circulation between the host tissue and the graft, blockage of blood circulation around the graft due to a compact structure of an extracellular matrix in the graft, the presence of a basement membrane layer, and a relatively higher thickness of the graft, blockage of bodily fluid circulation, a decrease in generation and migration of new blood vessels, restriction of proliferation of fibroblasts and endogenous collagen tissues, a foreign body sensation caused by an insufficient graft response, increased tendency for inflammation and infection, formation of a capsule of scar tissue around the graft, retention of bodily fluids, etc.
In the case of the acellular dermal tissue, the basement membrane layer is lined on an upper portion of the dermis, serves to strongly bind the dermis to the epidermis, and is attached to the dermis after removal of the epidermis. The basement membrane layer has a problem in that it may be slowly engrafted since its compact tissue significantly reduce an uptake rate of fibroblasts in the established graft site after transplantation, compared with other sites where no grafting is done.
In particular, most currently commercially available acellular dermal grafts have a problem in that they are transplanted in a quadrilateral shape, and thus the skin protrudes at the corners of the quadrilateral graft lined toward the surface of the skin, which leads to an unnatural external appearance. Also, since the front and rear surfaces of graft are not easily discriminated between with the unaided eye (for example, the basement membrane layer has a smooth surface, and a lower surface of the derma has a finely coarse surface), it is very difficult to find a way to discriminate between the front and rear surfaces of graft as required for transplantation. For rapid recovery of a patient after transplantation, it is also necessary to minimize skin incision at a graft site. In this case, a quadrilateral graft may not be easily grafted onto the graft site.